Heat-sensitive paint on radiators helps reduce energy waste

What unsustainable behavior needs to change:

Radiators in public buildings such as schools, libraries, etc. are often wasting energy in rooms that are not being occupied or where windows are opened. 

According to a study conducted by the Department of Energy and Climate Change in the UK, leaving a single window open overnight during winter can increase heating energy consumption by up to 8%. This means, if a person’s heating bill for the winter is $1000, leaving the window open for one night could potentially cost an additional $80.

The core problem: People cannot see if the radiator is hot, medium, or cold making it difficult to know if they should turn down the valve. 

The Krukow consultants worked together with the city of Copenhagen to investigate what kind of nudge solutions could be developed to reduce heat waste from radiators. 

The findings can be transferred to both companies and private households. 

Here is what Krukow found:

1. The main behavioural barrier for turning off a radiator when i.e., opening a window is lack of visual feedback. When opening a window, we pay little attention to the radiator and forget to put a hand on it to feel if it is hot or cold. 
2. There is nothing in the visual design of the radiator reminding people to check the heat of the radiator before opening the window.
3. When a window is open near a warm radiator, the heat goes up to compensate for the drop in room temperature making the heat of the radiator instantly increase even more. 

In a nutshell: People often fail to change unsustainable behaviour when unable to assess abstract factors like room temperature or air circulation.

The Green Nudge:

Krukow came up with the idea to add heat-sensitive paint to radiators, changing colour from blue to red to provide visual temperature feedback. 

When a radiator in a room compensates for a drop in temperature by increasing heat output, the heat-sensitive paint on the radiator’s surface reacts to the immediate increase in temperature by changing colour. This colour shift provides an immediate visual cue to pupils, employees or visitors in public buildings, indicating when to turn off the radiator. This way the City of Copenhagen could effectively reduce energy waste and save money on heating bills.

Visual feedback, like the blue stripe on a baby’s diaper or a razorblade’s colour change, makes the abstract concrete and is a great way to trigger behaviour change, as demonstrated by the radiator paint example.